Question: $ D = \left[\begin{array}{rrr}0 & 2 & 2 \\ 1 & 1 & 2 \\ 2 & 1 & 2\end{array}\right]$ What is $ D^{-1}$ ?
Answer: $ = \left[\begin{array}{rrr}0 & -1 & 1 \\ 1 & -2 & 1 \\ -\frac{1}{2} & 2 & -1\end{array}\right]$